Turbine engine components with chemical vapor infiltrated isolation layers

Abstract

An assembly for use in a gas turbine engine and method for making the same are described herein. The assembly comprising a CMC component, a metallic component spaced apart from the CMC component, and a spacer. The spacer having a first surface in contact with the CMC and a second surface opposite the first surface in contact with the metallic component, the spacer comprising a CMC substantially free of silicon metal with a porosity of between about 5 percent and about 40 percent by volume to chemically isolate the CMC component from the metallic component.

What is claimed is: 
     
       1. An assembly for use in a gas turbine engine, the assembly comprising
 a ceramic matrix composite component, wherein the ceramic matrix composite component comprises a preform including (1) ceramic fibers and (2) a ceramic matrix or a ceramic layer, 
 a metallic component spaced apart from the ceramic matrix composite component, and 
 a spacer having a first surface in contact with the ceramic matrix composite and a second surface opposite the first surface in contact with the metallic component, the spacer comprising a ceramic matrix composite substantially free of silicon metal with a porosity of between about 5 percent and about 40 percent by volume to chemically isolate the ceramic matrix composite component from the metallic component, wherein the ceramic matrix composite of the spacer comprises a preform including (1) ceramic fibers and (2) a ceramic matrix or a ceramic layer. 
 
     
     
       2. The assembly of  claim 1 , wherein the metallic component comprises a recess along a surface of the metallic component and the spacer is positioned within the recess of the metallic component. 
     
     
       3. The assembly of  claim 1 , wherein the metallic component comprises a chemical element that forms a eutectic with silicon. 
     
     
       4. The assembly of  claim 1 , wherein the ceramic matrix composite of the spacer is selected from a group consisting of a silicon carbide-silicon carbide ceramic matrix composite, an oxide-oxide ceramic matrix composite, a polymer-infiltration-pyrolysis ceramic matrix composite, or a combination thereof. 
     
     
       5. The assembly of  claim 1 , wherein the ceramic fibers are silicon carbide and the ceramic layer is silicon carbide. 
     
     
       6. The assembly of  claim 1 , wherein the stiffness of the spacer is between about 5 msi and about 40 msi. 
     
     
       7. The assembly of  claim 1 , wherein the spacer has a thickness between about 0.02 inches and about 0.04 inches. 
     
     
       8. The assembly of  claim 1 , wherein the width of the spacer is between about 0.1 inches and about 0.15 inches. 
     
     
       9. An assembly for use in a gas turbine engine, the assembly comprising
 a ceramic matrix composite component, wherein the ceramic matrix composite component comprises a preform including (1) ceramic fibers and (2) a ceramic matrix or a ceramic layer, 
 a metallic component spaced apart from the ceramic matrix composite component, 
 a seal positioned between the ceramic matrix composite component and the metallic component, the seal including a porous ceramic matrix composite to inhibit air passage between the ceramic matrix composite component and the metallic component, wherein the porous ceramic matrix composite of the seal comprises a preform including (1) ceramic fibers and (2) a ceramic matrix or a ceramic layer. 
 
     
     
       10. The assembly of  claim 9 , wherein the seal is a full segment and is in contact with the ceramic matrix composite component and the metallic component to prevent passage of cooling air between the metallic component and the ceramic matrix composite component. 
     
     
       11. The assembly of  claim 9 , wherein the seal is a partial segment in contact with at least one of the ceramic matrix component or the metallic component to allow a selected amount of cooling air to pass between the metallic component and the ceramic matrix composite component. 
     
     
       12. The assembly of  claim 9  wherein the metallic component comprises a recess along a surface of the metallic component for holding the seal. 
     
     
       13. The assembly of  claim 12 , wherein the metallic component comprises a chemical element that forms a eutectic with silicon. 
     
     
       14. The assembly of  claim 9 , wherein the ceramic matrix composite of the seal is selected from a group consisting of a silicon carbide-silicon carbide ceramic matrix composite, an oxide-oxide ceramic matrix composite, a polymer-infiltration-pyrolysis ceramic matrix composite, or any combination thereof. 
     
     
       15. The assembly of  claim 9 , wherein the stiffness of the seal is between about 5 msi and about 40 msi. 
     
     
       16. The assembly of  claim 9 , wherein the seal has a thickness between about 0.02 inches and about 0.04 inches. 
     
     
       17. The assembly of  claim 9 , wherein the width of the seal is between about 0.1 inches and about 0.15 inches. 
     
     
       18. A method for forming a ceramic matrix composite spacer for use in a gas turbine engine, the method comprising
 forming a ceramic matrix composite spacer comprising (1) fibers and (2) a ceramic matrix or a ceramic layer, wherein the ceramic matrix composite spacer comprises a porosity of between about 5 percent and about 40 percent by volume, and wherein the ceramic matrix composite spacer is substantially free of silicon metal, 
 positioning a first surface of the ceramic matrix composite spacer to contact a silicon containing ceramic matrix composite component, wherein the ceramic matrix composite component comprises (1) fibers and (2) a ceramic matrix or a ceramic layer, and 
 positioning a second surface of the ceramic matrix composite spacer within a recess of a metallic component. 
 
     
     
       19. The method of  claim 18 , wherein the forming the ceramic matrix composite spacer comprises chemical vapor infiltrating silicon carbide onto a preform of silicon carbide fibers.